Peculiar behavior of the Poisson's ratio of laminated fibrous composites

Abstract

The effective Poisson's ratio of laminated fibrous composites shows a peculiar behavior as it becomes larger than unity or less than zero. This behavior can be utilized in the design of composite structure with special functions. The laminate theory, a nonlinear programming technique and a heuristic approach are used to determine the laminate configurations with the maximum, zero and the minimum values of Poisson's ratio of general symmetric laminates. It is found that balanced angle-ply symmetric laminates yield the maximum value and unbalanced bidirectional symmetric laminates yield the minimum value of the ratio. Experimental results show good agreement with the analytical results.